Antiparasitic and insecticidal activities of sesquiterpene lactones and eudesmanes of four Asteraceae species from America

SOSA ANDREA MABEL; SALAMANCA CAPUSIRI EFRAIN; GIMENEZ ALBERTO; VERA NANCY ROXANA; BARDÓN ALICIA DEL VALLE; BORKOSKY SUSANA ALICIA

Tokushima

Simposio; ISPSA 2015-Inaugural Symposium of the Phytochemical Society of Asia 2015; 2015

Phytochemical Society of Asia and Tokushima Bunri University

Naturalproducts continue to be an important source for the search of new therapeuticdrugs and agrochemicals. Leishmaniasis is a major threat to public health inmany countries from South America. An alternative to antiparasitic syntheticdrugs is the search of plant extracts or secondary metabolites derived fromthem. Additionally, botanical insecticides and their bioactive chemicals aregenerally pest-specific and are relatively harmless to non-target organismsincluding man. We investigatedthe molluscicidal, leishmanicidal and insecticidal activities of ten lactonesand seven eudesmanes with sesquiterpenoid skeleton from four species ofAsteraceae: Vernonanthura nebularum, V. pinguis, Vernoniafulta, and Pluchea sagittalis. Leishmaniaamazonensis clone 1 (MHOM/BR/76/LTB-012) and L. braziliensis(RJA C192 M2904) promastigotes, the mollusk Biomphalaria peregrina, potentialvector of schistosomiasis and Spodoptera frugiperda and Ceratitiscapitata, pests that cause significant damage to crops in northwestern of Argentina, were used as experimentalmodels.   Elephantopus-typesesquiterpene lactones (SL) from Vernonanthura nebularum were the mostactive against the mollusk with LD50 values of 15.8 and 31.3 ppm forcompounds 8 and 10,respectively. In antiparasitic activity assays, all SL of V. nebularum (7-10),showed a strong effect on the promastigote forms of Leishmania amazonensisand L. brazilienzis, with IC50 values <3.9 mg/ mL for bothstrains. All SL tested exhibited a strong antifeedant activity againstS. frugiperda under choiceconditions, compound 1 being themost active with an antifeedant index (AI) of 82.16  at 100 ppm. The ingestion of eudesmanes 15-17by third instar larvae reduced growth and utilization of the ingested anddigested food significantly. Mortality rates of larvae and pupae do notexceeded 40% in all treatments. Finally, SL2 and eudesmanes 11 and 14 were the most active against C.capitata, inhibiting the oviposition rate 60%, 75% and 89%, respectively,at a dose of 30 µg/cm2.